Education Minister Jeremy Rockliff blamed industrial action being taken by the Australian Education Union over a wage rise.

Tasmania's public sector unions have planned a strike for Wednesday in protest over the Government's refusal to grant a 3 per cent per annum wage rise over three years.

They are holding stop-work rallies in Hobart, Launceston, Devonport and St Helens at 3:00pm as they continue their fight for the pay rise.

Mr Rockliff said the Government's offer of 2 per cent, which has been in place since 2011, was "fair and affordable" and enabled the employment of more teachers.

Unions have said Wednesday will be the biggest industrial action Tasmania has seen for decades.

Teachers who plan to attend the rally would need to leave school by 2:00pm, hence the Government's call to close them early.

"Student safety remains the Government's primary concern," Mr Rockliff said in a statement.

"I have been guided by advice from the Department of Education on the impacts of staff leaving the workplace to attend stop-work rallies on the safety and wellbeing of students."

The list of schools to close early includes primary and high schools, with finishing times from as early as 1:30pm.

'Enough is enough, a line has been drawn'

Roz Madsen with the Australian Education Union said teachers did not take industrial action lightly but wanted improved workloads and pay from the state.

"They do it reluctantly but enough is enough, a line has been drawn," she said.

"Educators are feeling completely disrespected by this Hodgman Government."

Teachers will be joined by nurses, firefighters and other public sector workers in the stop-work action.

Community and Public Sector Union secretary Tom Lynch said there would be disruptions to hospitals and Service Tasmania outlets as well as schools.

"We say to them, 'We're sorry'," he said.

"We're sorry that this government has pushed us to the stage where our members have to take industrial action that denies you the services you rely on every day."

Treasurer Peter Gutwein said the Government's wage offer was fair.

"I think many parents will be left wondering what's going on on Wednesday when their lives are disrupted, the lives of their children are being disrupted when teachers are being offered a 6 per cent wage increase over the next three years," he said.

'Good for them': Social media users get behind teachers

Despite the pick-up chaos the rally is likely to cause, there was strong support for teachers on social media.

"Thank you to our incredible teachers, who work so hard to provide quality education to our kids in a challenging environment. You deserve a pay rise, and to be afforded due respect for the work you do," Kristy Bunny Alger wrote on Facebook.

"Good for them. This Government hands itself pay rises while denying them to our most important workers," Jo Bain said.

Sonja Preston said: "Support for teachers is imperative, and this [means] paying them well!"